A reminder of the respective limitations of affidavit and oral evidence, when one method might be preferred over another, and what, if any, reliance should be placed on witnesses’ recollections of events and conversations
The case is Linfield Developments Pty Limited v Shuangxing Development Pty Limited  NSWSC 68 per Pembroke J at  to , extracted in full below.
“10. I should make some preliminary remarks about the affidavit and oral evidence of the witnesses. As always, the contemporaneous written records created before the threat of litigation were a more reliable indicator of what occurred than the competing contentious accounts of conversations drafted at a later date under the guiding hand of a party’s solicitor. As I said in Mealey v Power  NSWSC 1678 at : ‘…what matters most is usually the proper construction of such contemporaneous notes and documents as may exist, and the probabilities that can be derived from those notes and any other objective facts’.
11. The limitations of affidavits as vehicles for conveying an accurate account of past oral communications are well-known. In Thomas v SMP (International) Pty Ltd  NSWSC 822, I set out some of the considerations:
‘ … Affidavits have an important function and serve a useful purpose. But they are not necessarily always the best means of leading evidence-in-chief. Where there are disputed issues of fact involving oral representations and conversations, affidavit evidence can sometimes be an unsatisfactory medium for leading the evidence-in-chief.
 It is well known that eminent jurists with unparalleled trial experience have expressed misgivings about the elicitation of evidence-in-chief by affidavits in cases whose success or failure depends on disputed representations and conversations. A colourful but apposite aphorism frequently invoked by Hon T E F Hughes QC, and attributed to Lord Buckmaster, is that “the truth sometimes leaks out of an affidavit – like water from the bottom of a well”…
 Justice Emmett elaborated more fully on the difficulties to which affidavits and witness statements can give rise in Practical Litigation in the Federal Court of Australia – Affidavits (2001) 20 Australian Bar Review 28:
‘Where evidence is controversial, particularly where credibility of the witness is involved, the adducing of the evidence in written form is often undesirable and can be quite unfair… With the very best of intentions a lawyer who settles an affidavit or a witness statement will invariably reduce the language of the witness to the lawyer’s own language. That may entail changes in meaning and emphasis that, although not intended, may expose a witness to unnecessary difficulties in the course of cross-examination. On the other hand, a dishonest witness will always be assisted by having evidence put into credible form by a lawyer…’
 In 1996 in the Access to Justice Report, Final Report (HMSO), 1996 at , Lord Woolf pithily observed:
Witness statements have ceased to be the authentic account of the lay witness; instead they have become an elaborate, costly branch of legal drafting.
 And as long ago as 1975, the New South Wales Law Reform Commission, inWorking Paper 14, (1975) – Procedure: Common Law Pleadings, also observed (paragraph 7.3): “affidavit evidence is said (and with justification) to be more the evidence of the legal advisor than the witness”.
 A common thread in the commentary is that the studied reconstruction, and formulation in writing, of contentious conversations and oral communications in language that is usually settled and refined by lawyers, can sometimes be unreliable and unintentionally misleading. …’
12. While affidavits are, for those reasons, often unreliable touchstones of the truth, oral evidence is frequently also unreliable for a different reason. In Watson v Foxman (1995) 49 NSWLR 315 at 319 McLelland CJ in Eq succinctly stated what we all recognise as an everyday aspect of the judicial process:
‘…human memory of what was said in a conversation is fallible for a variety of reasons, and ordinarily the degree of fallibility increases with the passage of time, particularly where disputes or litigation intervene, and the processes of memory are overlaid, often subconsciously, by perceptions or self-interest as well as conscious consideration of what should have been said or could have been said.’
13. Lord Pearce explained these issues, and emphasised the ‘utmost importance’ of contemporary documents, in his speech in Onassis and Calogeropoulos v Vergottis  2 Lloyd’s Rep 403 at 431, a successful appeal by a litigant named Aristotle Socrates Onassis:
‘Credibility covers the following problems. First, is the witness a truthful or untruthful person? Secondly, is he, though a truthful person, telling something less than the truth on this issue, or, though an untruthful person, telling the truth on this issue? Thirdly, though he is a truthful person telling the truth as he sees it, did he register the intentions of the conversation correctly and, if so, has his memory correctly retained them? Also, has his recollection been subsequently altered by unconscious bias or wishful thinking or by overmuch discussion of it with others? Witnesses, especially those who are emotional, who think that they are morally in the right, tend very easily and unconsciously to conjure up a legal right that did not exist. It is a truism, often used in accident cases, that with every day that passes the memory becomes fainter and the imagination becomes more active. For that reason a witness, however honest, rarely persuades a Judge that his present recollection is preferable to that which was taken down in writing immediately after the accident occurred. Therefore, contemporary documents are always of the utmost importance.’
14. Given those considerations, a healthy scepticism about the reliability of affidavit and oral evidence of conversations is often justified – in many types of cases but especially in commercial cases. In recent times, no one has put the matter quite so decisively as Leggatt J in Gestmin SGPS SA v Credit Suisse (UK) Ltd  EWHC 3560 (Comm) at :
‘…the best approach for a judge to adopt in the trial of a commercial case is, in my view, to place little if any reliance at all on witnesses’ recollections of what was said in meetings and conversations, and to base factual findings on inferences drawn from the documentary evidence and known or probable facts.’
He added perceptively however:
‘This does not mean that oral testimony serves no useful purpose – though its utility is often disproportionate to its length. But its value lies largely, as I see it, in the opportunity which cross-examination affords to subject the documentary record to critical scrutiny and to gauge the personality, motivations and working practices of a witness, rather than in testimony of what the witness recalls of particular conversations and events.’
(For those interested, a full extract of the relevant passages of Gestmin appears below):
“Evidence based on recollection
15. An obvious difficulty which affects allegations and oral evidence based on recollection of events which occurred several years ago is the unreliability of human memory.
16. While everyone knows that memory is fallible, I do not believe that the legal system has sufficiently absorbed the lessons of a century of psychological research into the nature of memory and the unreliability of eyewitness testimony. One of the most important lessons of such research is that in everyday life we are not aware of the extent to which our own and other people’s memories are unreliable and believe our memories to be more faithful than they are. Two common (and related) errors are to suppose: (1) that the stronger and more vivid is our feeling or experience of recollection, the more likely the recollection is to be accurate; and (2) that the more confident another person is in their recollection, the more likely their recollection is to be accurate.
17. Underlying both these errors is a faulty model of memory as a mental record which is fixed at the time of experience of an event and then fades (more or less slowly) over time. In fact, psychological research has demonstrated that memories are fluid and malleable, being constantly rewritten whenever they are retrieved. This is true even of so-called ‘flashbulb’ memories, that is memories of experiencing or learning of a particularly shocking or traumatic event. (The very description ‘flashbulb’ memory is in fact misleading, reflecting as it does the misconception that memory operates like a camera or other device that makes a fixed record of an experience.) External information can intrude into a witness’s memory, as can his or her own thoughts and beliefs, and both can cause dramatic changes in recollection. Events can come to be recalled as memories which did not happen at all or which happened to someone else (referred to in the literature as a failure of source memory).
18. Memory is especially unreliable when it comes to recalling past beliefs. Our memories of past beliefs are revised to make them more consistent with our present beliefs. Studies have also shown that memory is particularly vulnerable to interference and alteration when a person is presented with new information or suggestions about an event in circumstances where his or her memory of it is already weak due to the passage of time.
19. The process of civil litigation itself subjects the memories of witnesses to powerful biases. The nature of litigation is such that witnesses often have a stake in a particular version of events. This is obvious where the witness is a party or has a tie of loyalty (such as an employment relationship) to a party to the proceedings. Other, more subtle influences include allegiances created by the process of preparing a witness statement and of coming to court to give evidence for one side in the dispute. A desire to assist, or at least not to prejudice, the party who has called the witness or that party’s lawyers, as well as a natural desire to give a good impression in a public forum, can be significant motivating forces.
20. Considerable interference with memory is also introduced in civil litigation by the procedure of preparing for trial. A witness is asked to make a statement, often (as in the present case) when a long time has already elapsed since the relevant events. The statement is usually drafted for the witness by a lawyer who is inevitably conscious of the significance for the issues in the case of what the witness does nor does not say. The statement is made after the witness’s memory has been “refreshed” by reading documents. The documents considered often include statements of case and other argumentative material as well as documents which the witness did not see at the time or which came into existence after the events which he or she is being asked to recall. The statement may go through several iterations before it is finalised. Then, usually months later, the witness will be asked to re-read his or her statement and review documents again before giving evidence in court. The effect of this process is to establish in the mind of the witness the matters recorded in his or her own statement and other written material, whether they be true or false, and to cause the witness’s memory of events to be based increasingly on this material and later interpretations of it rather than on the original experience of the events.
21. It is not uncommon (and the present case was no exception) for witnesses to be asked in cross-examination if they understand the difference between recollection and reconstruction or whether their evidence is a genuine recollection or a reconstruction of events. Such questions are misguided in at least two ways. First, they erroneously presuppose that there is a clear distinction between recollection and reconstruction, when all remembering of distant events involves reconstructive processes. Second, such questions disregard the fact that such processes are largely unconscious and that the strength, vividness and apparent authenticity of memories is not a reliable measure of their truth.
22. In the light of these considerations, the best approach for a judge to adopt in the trial of a commercial case is, in my view, to place little if any reliance at all on witnesses’ recollections of what was said in meetings and conversations, and to base factual findings on inferences drawn from the documentary evidence and known or probable facts. This does not mean that oral testimony serves no useful purpose – though its utility is often disproportionate to its length. But its value lies largely, as I see it, in the opportunity which cross-examination affords to subject the documentary record to critical scrutiny and to gauge the personality, motivations and working practices of a witness, rather than in testimony of what the witness recalls of particular conversations and events. Above all, it is important to avoid the fallacy of supposing that, because a witness has confidence in his or her recollection and is honest, evidence based on that recollection provides any reliable guide to the truth.
23. It is in this way that I have approached the evidence in the present case.”